The present invention relates to an antenna for mobile phone, and more particularly to an antenna for mobile phone that uses a printed circuit to replace the conventional coil antenna, so that the antenna is manufactured at reduced cost and provides increased frequency stability.
With the increasingly grown technology nowaday, mobile phones have not only largely reduced dimensions but also changeful appearances. However, most mobile phones have an antenna that is almost unchanged--a black, thick and short bar projected from a top of the mobile phone and having simple functions of receiving and transmitting signals. There are manufacturers developing some antennas for mobile phone that are able to emit lights, in addition to receive and transmit signals, enabling users to know current conditions of their mobile phones through not only sound and vibration, but also light.
FIG. 7 is an exploded perspective showing the structure of a conventional antenna 1 for mobile phone. The antenna 1 mainly includes a clear hood 11, an antenna 12, a light-emitting element 13, a separating plate 14, an insulating member 15, a signal needle 16, a coiled member 17, and a base 18. The separating plate 14 is fixedly connected to a top of the signal needle 16 for setting in the coiled member 17. The separating plate 14 prevents the antenna 12 from contacting with the coiled member 17 and thereby protects the antenna 12 against short circuit that would cause failure of the antenna 12 in receiving and transmitting signals. An upper side of the separating plate 14 is electrically conductive for a lower end of the antenna 12 and a first pin of the light-emitting element 13 to fixedly weld thereto. The base 18 is in the form of a funnel and is provided with an axially extended through hole 181. The through hole 181 is provided on an inner peripheral wall with an insulting layer to prevent the signal needle 16 located in the through hole from unexpected contacting with the base 18 to result in short circuit and failure in receiving and transmitting signals. The insulting member 15 is a cylindrical member connected to and around the signal needle 16, such that the insulting member 15 is set in an upper end of the through hole 181. A second pin of the light-emitting element 13 is welded to a top of the coiled member 17. The base 18 has an externally threaded portion for the base 18 to screw onto a top of a mobile phone and contact with a negative electrode of a power supply in the mobile phone. Finally, the clear hood 11 is closed onto the base 18 to enclose the antenna 12.
The above-described conventional antenna for mobile phone has complicate components that could not be easily assembled together, and therefore requires increased manufacturing cost and selling price. The above-described conventional antenna for mobile phone also has the following drawbacks:
1. The high number of complicate components tends to result in errors in assembling the antenna to adversely affect the quality of received signals. PA1 2. In the conventional antenna that also emits lights, a voltage signal at the output of the antenna has a maximum value equal to a peak value Vm thereof, and only limited number of light-emitting elements (loads) at the output can be driven by the output voltage to emit lights.
In view of the drawbacks existing in the conventional antenna for mobile phone, it is tried by the inventor to develop an improved antenna for mobile phone to eliminate such drawbacks.